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dc.contributor.authorHan, Liangen_US
dc.date.accessioned2017-09-16T06:00:28Z
dc.date.available2017-09-16T06:00:28Z
dc.date.issued2016-03-24en_US
dc.identifier.othervt_gsexam:7181en_US
dc.identifier.urihttp://hdl.handle.net/10919/78906
dc.description.abstractContinental rifting ultimately creates a deep accommodation space for sediment. When a major river flows into a late-stage rift, thick deltaic sediment can change the thermal regime and alter the mechanisms of extension and continental breakup. The Salton Trough, the northernmost rift segment of the Gulf of California plate boundary, has experienced the same extension as the rest of the Gulf, but is filled to sea level by sediment from the Colorado River. Unlike the southern Gulf, seafloor spreading has not initiated. Instead, seismicity, high heat flow, and minor volcanoes attest to ongoing rifting of thin, transitional crust. Recently acquired controlled-source seismic refraction and wide-angle reflection data in the Salton Trough provide constraints upon crustal architecture and active rift processes. The crust in the central Salton Trough is only 17-18 km thick, with a strongly layered but relatively one-dimensional structure for ~100 km in the direction of plate motion. The upper crust includes 2-3 km of Colorado River sediment. The basement below the sediment is interpreted to be similar sediment metamorphosed by the high heat flow and geothermal activity. Meta-sedimentary rock extends to at least 7-8 km depth. A 4-5 km thick layer in the middle crust is either additional meta-sedimentary rock or stretched pre-existing continental crust. The lowermost 4-5 km of the crust is rift-related mafic magmatic material underplated from partial melting in the hot upper mantle. North American lithosphere in the Salton Trough has been almost or completely rifted apart. The gap has been filled by ~100 km of new transitional crust created by magmatism from below and sedimentation from above. These processes create strong lithologic, thermal, and rheologic layering. Brittle extension occurs within new meta-sedimentary rock. The lower crust, in comparison, stretches by ductile flow and magmatism is not localized. This seismic interpretation is also supported by 1D thermal and rheological modeling. In this passive rift driven by far-field extensional stresses, rapid sedimentation keeps the crust thick and ductile, which delays final breakup of the crust and the initiation of seafloor spreading.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectactive riftingen_US
dc.subjectcrustal structureen_US
dc.subjectSalton Troughen_US
dc.subjectseismic tomographyen_US
dc.subjectcontrolled-source seismicen_US
dc.subjectmetamorphismen_US
dc.subjectthermal modelingen_US
dc.titleseismic imaging and thermal modeling of active continental rifting processes in the Salton Trough, Southern Californiaen_US
dc.typeDissertationen_US
dc.contributor.departmentGeosciencesen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeosciencesen_US
dc.contributor.committeechairHole, John Andrewen_US
dc.contributor.committeechairLowell, Robert P.en_US
dc.contributor.committeememberBodnar, Robert J.en_US
dc.contributor.committeememberStock, Joann M.en_US
dc.contributor.committeememberChapman, Martin C.en_US


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